this is what i committed to fix things:
sim/bfin/:
sim/cris/:
sim/lm32/:
sim/m68hc11/:
sim/mips/:
sim/mn10300/:
2011-10-19  Mike Frysinger  <vapier@gentoo.org>

	* configure: Regenerate after common/acinclude.m4 update.

sim/common/:
2011-10-19  Mike Frysinger  <vapier@gentoo.org>

	* acinclude.m4: Call AC_CHECK_LIB when $hardware contains cfi.
-mike

--- common/acinclude.m4
+++ common/acinclude.m4
@@ -623,7 +623,11 @@ if test "$sim_hw_p" != yes; then
 fi
 if test x"$silent" != x"yes"; then
   echo "Setting hardware to $sim_hw_cflags, $sim_hw, $sim_hw_objs"
-fi])dnl
+fi])
+dnl Some devices require extra libraries.
+case " $hardware " in
+  *" cfi "*) AC_CHECK_LIB(m, log2);;
+esac
 ])
 AC_SUBST(sim_hw_cflags)
 AC_SUBST(sim_hw_objs)